A multitude of gate systems are known whereby to restrict passage or control the passage of people in specific areas. Some of these systems are in the form of complicated barriers or turnstile systems or simply a single arm which is pivotally connected at one end by a pivoting mechanism permitting passage in a single direction. An example of such single arm systems is disclosed in U.S. Pat. No. 5,561,520. Many of these systems are complex in design and are therefore subject to wear and breakage and require frequent maintenance. This can be a nuisance particularly if such gates become broken and locked preventing a person from entering into an establishment such as a supermarket.
Another disadvantage of known prior art one-way self-closing gates is that many of these gates permit passage in only a single direction and in an emergency situation it is not possible or very difficult to exit an establishment through these barriers. Another disadvantage of some of these entrance gate systems is that they do not provide alarms if they are misused such as person trying to exit therethrough and therefore require periodic surveyance. Still further, some of these entrance gate systems permit easy undetected exit therethrough by a person maintaining the barriers or a pair of barriers in a double-gate system, in an open position for a long period of time permitting exit therethrough of another person and even the passage of shopping carts.